Car retarder control system



Aug. 10, 1965 BRocKMAN CAR RETARDER CONTROL SYSTEM Filed Jan. 23, 1962 United States Patent O 3,2%,2456 CAR RETMlDiiR CNTRL SYSTEM Lyle Broekman, Rochester, NE., assigner to General Signal Corporation, a corporation et New `lork Filed lan. 23, 1962, Ser. No. 168,657 12 Claims. (El. 246-182) i This invention generally relates to car retarder control systeins for railway classification yards and more particularly pertains to control of car retarders in accordance with the actual coupling speeds of the railway cars being classified.

In modern day classification yards, the cars being classified are allowed to roll from the yard hump and are then automatically routed, by suitable automatic switching, to their respective designated storage tracks. In order to control the speed at which the cars couple on their designated storage tracks, certain car retarders are strategically located between the yard hump and the storage tracks. These retarders are then controlled in accordance with the various factors alecting the free rolling movement of the railway cars being classified, such as rolling resistance, weight and distance to coupling point, so that each railway car will arrive at its coupling point at a sate coupling speed.

Normally, during installation, the car retarder control apparatus is manually adjusted, in accordance with existing yard conditions, to obtain the desired safe coupling speeds during car classification. However, because of changing weather conditions, for example, the actual coupling speeds may vary excessively, from the desired safe speed and therefore, the need exists for a means to continually and automatically adjust the car retarders in accordance with the actual coupling speeds at which the cars are coupling on their respective storage tracks.

In View of the above considerations, itis proposed in accordance with the present invention to provide for detecting the actual speed of railway cars at substantially the coupling points for these cars and to then utilize these detected coupling speeds for car retarder adjusting purposes. Thus, if the railway cars are generally arriving at their respective coupling points at too high a speed, the retardation or braking action applied to subsequent cars by the car retarders is increased, whereas, if the actual coupling speeds are generally too slow, the braking action ofthe retarders is decreased. For example, in the selected embodiment shown herein, a computer controls the release speed of a retarder, or in other words, the speed to which the retarder is controlled to open to a non-braking position, and the actual coupling speed is utilized to adjust this computed release speed for controlling the braking action of the retarders. In this way, the car retarders can be continually and automatically adjusted so as to maintain the actual coupling speeds at substantially the predetermined desired safe coupling speed.

One object of the present invention is therefore to provide a car retarder control system wherein the actual coupling speed of the railway cars is utilized to adjust the car retarders in a railway classification yard.

A further object of the present invention is to provide for selectively increasing and decreasing the braking actionof a car retarder in accordance with the actual coupling speeds of cars being classified in a railway classiiication yard.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part'pointed out as the description of the invention progresses.

In describing the invention in detail, reference will he made to the accompanying drawings, in which like reference characters designate corresponding parts, and in which:

3,2%,245 Patented Aug'. l0, i965 FIG. l diagrammaticaliy illustrates one specific embodiment of the present invention for controlling a car retarder in accordance with the actual coupling speeds of cars being classiied in a railway classification yard; and

FIG. 2 illustrates in more detail a specific circuit arrangement associated With the selected embodiment of the present invention.

For the purpose of simplifying the illustration and facilitating in the explanation, various parts and circuits constituting the selected embodiment of the invention have been shown diagrammatically and certain conventional illustrations have been employed, the drawings have been made more with the purpose of making it easy to understand the principles and mode of operation, than with the idea of illustrating the Specific construction and arrangement of parts that would be employed in practice. For example, the symbols and are employed to indicate the positive and negative terminals respectively of suitable batteries, or other source of direct current and the various relays utilized in the selected embodiment are illustrated in a conventional manner with the various contacts of the relays shown as being in a lower or inclined position when the coil or winding of the associated relay is deenergized, and in a raised or horizontal position when the relay is energized; the contacts belonging to any given relay are shown connected to its coil or winding by dotted lines.

Referring now to the accompanying drawings, a partial track layout, typical of railway classication yards, is illustrated and includes a group track GT extending through track switch SW to the various storage tracks on which the railway cars being classified are stored. A retarder GR is located on group track GT and is utilized to control the speed at which the various cars being classied are permitted to enter those storage tracks associated with group track GT. For example, retarder GR is selectively actuated to control the railway cars designated for storage track ST1.

The entrance end of storage track ST1 is defined by the insulated joints at point E, and, connected across this entrance end of storage track ST1 is a constant current source 10 capable of energizing the rails of storage track ST1 with a constant magnitude current irrespective of Vvthe position of any railway cars on the storage track ST1.

Because of the shunt properties of a railway car, this current from constant current Isource 10 is confined to a track circuit behind the rear axle of the last car having entered storage track ST1, and, because of the linear impedance characteristics of the storage track rails, a voltage signal will appear at the entrance end of storage track ST1 which is directly proportional to, or is analog of, the distance from the entrance end E of storage track ST1 and the position of the last car having entered this storage track.

This analog voltage signal, from the entrance end E of storage track ST1, is applied through step-up transformer T1 to a full-wave rectifier FWl whose output, at resistor '11, is a D C. voltage analog of the distance between the entrance end of the storage track ST1 and the position of the last car having entered track ST1. This DC. analog voltage is then applied as input to a conventional different-iator l2 so that the output appearing on wire 13 is a D.C. analog of the speed of the last car having entered storage track ST1.

This speed analog voltage is then applied to a linear amplifier 14, utilized to increase the magnitude of the speed analog voltage, and th-e output of linear amplifier 14 is fed along wire 15 to the speed voltage storage 16 which is intended here t-o be any suitable storage capable of storing the actual speed of a railway car as it is traversing storage track ST1.

illustrated in FIG. l. An example of such a motion detector is disclosed in detail in the U.S. application of K. H. Frielinghaus, Ser. No. 22,191, filed April 14, 1960,v

and assigned to the same assignee as the present application. v Y

From the accompanying drawings it will be noted that as long as the motion detector relay MD is picked up (motion occurring) the output of the speed voltage storage 16 is disconnected from the coupling speed register 19. However, as soon as the motion detector relay MD drops away, back contact 20 of relay MD is closed and the speed analog voltage then stored on the speed voltage storage 16 is applied as input to the coupling speed regisrter 19. Obviously, the speed voltage storage 16 must have the proper time delays incorporated into its associated circuit networks so that, when the motion detector relay MD drops away, the speed analog voltage then applied to the coupling speed register 19 will be indicative of the speed of a car at substantially the coupling point for that car.

The coupling speed register 19k then controls relays U24 and O4R which are selectively venergized to register if the railway car is under two miles-per-hour or over four miles-per-hour, respectively, when it arrives at its coupling point; the range of two to four miles-per-hour being arbitrarily assumed as the safe coupling speed range for the purpose of disclosure. These relays UZR and O4R then operate to selectively energize the upper and lower halves of winding WW, intended here to be part of a so-called rachet relay, and therefore control the positioning of contact arm 21 on register 22, so that the voltage appearing on contact arm 21 rwill indicate lthe necessary adjustment required of retarder GR in order that thebraking action of the retarder will be decreased (release speed increased) if the railway cars are coupling too slow (below two miles-per-hour) and the braking action increased (release speed decreased) if the cars are coupling too fast (above four miles-perhour).

This voltage signal appearing on contact arm 21 is fed along wire 23 to the release speed computer 24, as the Coupling Speed Correction. Also applied as inputs to the release speed computer 24 are various other factors normally required to forecast the amount of braking action necessary by car retarder GR; i.e. rolling resistance, weight, distance to coupling, etc. This release speed computer 24 then utilizes these various inputs to solve the preset computer equations and subsequently controls the retarder control apparatus 25 so as to position the retarder GR correctly for supplying the desired amount of retardation or braking action to the railway cars Abeing routed onto storage trackSTl, in order to cause proper coupling of the cars.

In order to more fully describe the operation of the selected embodiment of the present invention, it will now be assumed that a railway car C3 (see FIG. l) enters storage track ST1 and is to be coupled onto cars C2 and -C1 already stored on storage track ST1. As previously mentioned, the constant current source supplies a constant magnitude current to the track yrails of storage track ST1 and thereby causes a voltage to appear at the -entrance end (point E) of storage track ST1 which is directly proportional to, or is the analog tof, the distance between the entrance end of storage track ST1 and the position of the railway car C3. Since the car C3 is in motion, the voltage applied to the primary side of trans- ,former T1 is increasing in magnitude, and therefore, the

voltage signal appearing across resistor 11, at the output y.of the full wave rectifier FWl, is a D C. analog voltage whose magnitude is also increasing with time.

This DC. analog voltage appearing across resistor 11 is then fed as input to the differentiating circuit 12 so that the output appearing on wire 13 is the analog of the speed at which car C3 is traversingstorage track ST1. As previously mentioned, this speed analog voltage is amplified in the linear amplifer 14 and is fed along wire 15 as input to the speed voltage storage 16. More specifically, with reference to FIG. 2, the speed analog voltage output from linear amplier 14 is fed along wire 15, through diode 2d, and is stored upon storage capacitor 27, the rate at which this speed analog voltage is stored on cav pacitor 27 being determined substantially by the known output impedance of linear amplifier 14.

The output of full-wave rectifier FWI is also fed along wire 17 to the motion detector 18 (see FIG. 1). This motion detector 13 may be of any suitable form and is assumed here to be a circuit organization, such as is disclosed in the above-mentioned Frelinghaus application Ser. No. 22,191, filed April 14, 1960, which selectively operates the motion detector relay MD in accordance with whether or not the D.C. analog voltage appearing across resistor 11 is varying with time. Thus, in this embodyiment, motion detector 18 is assumed to detect the motional status of storage track ST1 by comparing the magni-Y tudes of two successively accepted values of the D.C. analog voltage and maintains rnotion detector relay MD picked up as long las these two successively accepted values are different, and, deenergizes the motion detector relay MD when these two successively accepted values are indicative of the same distance between the entrance end of the storage track ST1 and the position of the railway cai C3; that is, the car has stopped.

Referring now to FIG. 2 when the motion detector relay MD drops away, indicating that the car C3 has coupled onto car C2, its back contact 20 is closed and the voltage then stored on storage capacitor 27 is applied to the coupling speed register 19, shown in FIG. 2, as

'19 includes relays U2R and 04R, diodes 28 and 29,

including relays U2R and O4R, diodes 28 and 29 and resistor 30.

From the above, it should be obvious that it is desirable to have storage capacitor 27 charge at a relatively rapidrate so that it can quickly charge up to a voltage indicative of the speed of car C3 as it enters storage track ST1. However, since the speed of car C3 will normally be decreasing as it traverses track ST1, due to rolling resistance and the like, the charge on storage capacitor 27 must also be able to follow the decreasing speed analog voltage appliedon wire 15, and therefore, the value of resistor R1 is selected small enough to permit the rate of discharge through front contact 31 of relay MD necessary to maintain the voltage on storage capacitor 27 indicative of the actual speed of car C3, but, resistor R1 must also be of suicient value to prevent appreciable discharge, of storage capacitor 27, between the time when the car iirst couples and the motion detector relay MD drops away. Furthermore, the resistor R2, connected to the back contact 20 of the 'motion detector MD, must be of suicient value to cause a relatively slow discharge of the storage capacitor 27, with relay MD released, so that the voltage applied as input to the coupling speed register'19 will be indicative of the actual coupling speed for the railway car C3.

As mentioned previously, coupling speed register and resistor 30 which is connected between and ground. Assuming the car C3 is coupled, the coupling speed analog voltage stored on capacitor 27 is applied to resistor R2 at the input of power amplifier 32 which is provided to insure that suflicient power will be available for proper operation of relays U2R and O4R. More specically, the output voltage of power amplifier 32 appearing on wire 33 is then compared with predetermined voltages preset in accordance with the desired safe coupling speed range, as dictated by the position of taps 34 and 35 on resistor 30. More specifically, tap 34 is preset so that the diode 29 conducts and the relay O4R is picked up if the coupling speed analog voltage 0n wire 33 is indicative of a coupling speed greater than four miles-per-hour, while the tap 35 is preset so that the diode 28 conducts and the relay U2R picks up if the coupling speed analog voltage, on wire 23 is indicative of a coupling speed less than two miles-perhour.

The relays U2R and O4R then selectively control the positioning of contact arm 21 on resistor 22. More specifically, the picking up of relay O4R causes arm 21 to be stepped downwardly on resistor 22 due to the energization of the lower half of winding WW by a circuit extending from through front contact 36 of relay OtR, and to while the picking up of relay UZR causes arm 21 to be stepped upwardly on resistor 22 due to the energization of the upper half of winding WW by a circuit including front contact 37 of relay UZR. As mentioned previously, the winding WW forms part of a rachet relay and causes contact arm 21 to step up or down onresistor 22 in accordance with the operation of relay UZR and' OiR respectively for increasing and decreasing, respectively, the release speed computed for control of retarder GR, and therefore, the amount or retardation applied to a railway car by the retarder.

For example, in this selected embodiment of the present invention, the contact arm 21 is normally preset to pick up a voltage from resistor 22 indicative of a zero coupling speed correction, for application to the release speed computer 24 and the operation of relay UZR and O/lR then could cause this voltage to be increased and decreased, in one-tenth mile-per-hour steps, for adjusting the retarder to supply the correct amounts of retardation to the cars traveling therethrough in order to hold the actual coupling speeds of the cars within the desired limits.

Having thus described a car retarder control system as one specific embodiment of the present invention, it should be understood Ithat this form is selected to facilitate in the disclosure of the invention rather than to limit the number of forms which it may assume; and, it is to be further understood that various modifications, adaptations and alterations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention.

What I claim is:

1. In a car retarder control system for a railway classification yard having a car retarder for adjusting the speed at which the cars being classified couple on their assigned storage tracks, the combination of,

(a) detection means for detecting the speed of a first car being classified substantially at the point of coupling on its assigned storage track, and

(b) control means responsive to the condition of said detection means operative to control said car retarder to adjust the speed of a subsequent car being classified in accordance with the coupling speed of said first car detected by said detection means.

2. The control system specified in claim 1 wherein said control means are effective to selectively increase or decrease the braking action applied by said car retarder to said subsequent car dependent upon whether the coupling speed of said first car detected by said detection means is above orbelow a predetermined desired coupling speed value.

3. In a car retarder control system for a railway classiiication yard having a car retarder for adjusting the speed at which the cars being classified couple on their assigned storage tracks, the combination of,

(a) registering means for registering the speed of a first car on its assigned storage track,

(b) detecting means for detecting when said first car reached its coupling point, and

(c) means responsive to said registering means and said detecting means for controlling said car retarder in accordance with the speed of said car at said coupling point.

4. In a car retarder control system for a railway classification yard having a car retarder for adjusting the speed at which the cars being classified couple on their assigned storage tracks, the combination of, y

(a) means for producing a signal proportional to the speed of a lirst car on its assigned storage track,

(b) means for continually storing said signal while said first car is moving on said storage track towards its coupling point,

(c) means for detecting when said first car reaches said coupling point, and

(d) means responsive to the condition of said storage means and said detecting means for controlling said car retarder to adjust the speed of a subsequent car being classified in accordance with the value of said signal' stored on said storage means when said first y car reaches said coupling point.

5. The control system specified in claim 4 wherein said control means are effective to selectively increase or decrease the braking action of said car retarder dependent upon whether the signal stored on said storage means is above or below predetermined values when said first car reaches said coupling point.

6. In a car retarder control system for a railway classification yard having a car retarder for adjusting the speed at which the cars being classified couple on their assigned storage tracks, the combination of,

(a) means for producing a first signal proportional to the position of a first car on its assigned storage track,

(b) means responsive to said iirst signal for producing a second signal proportional to the speed of said iirst car on said storage track,

(c) means for continually storing said second signal while said first car is moving on said storage track toward its coupling point,

(d) means for detecting when said first car reaches said coupling point, and

(e) means responsive to the condition of said storage means and said detecting means for controlling said car retarder to adjust the speed of a subsequent car being classified in accordance with the value of said second signal stored on said storage means when said first car reaches said coupling point.

7. The control system speciiied in claim 6 wherein said first signal producing means include a constant current source connected across the rails at the entrance end of said storage track for causing a voltage to be developed which is proportional to the distance from said entrance end to the nearest car on said storage track.

8. The control system specified in claim 6 wherein said second signal producing means includes means for differentiating said first signal to produce said second signal.

9. In a car retarder control system for a railway classification yard having a car retarder for adjusting the speed at which the cars being classified couple on their assigned storage tracks, the combination of,

(a) release speed computer means for computing the car speed at which said car retarder is to be controlled to an open position to release the braking action ot' said car retarder on a car traveling therethrough,

(c) means for detecting the speed of a first car substantially at the coupling point on its assigned storage track, and

(d) means responsive to said detection means for providing an input to said computer means having a bearing on the computed release speed for a subse- 7 x quentfcar being classified inY accordance with the detected coupling speed of said first car.

10. The control system specified in claim 9 wherein said input providing means include,

(a) means responsive to said detecting means for comparing the detected coupling speed of said first car with a predetermined desired coupling speed, and

(b) means for producing an input to said computer means having a bearing on the computed release speed of said subsequent car in accordance with the condition of said comparing means.

11. In a system for detecting the speed of a railway car substantially at the coupling point of said car on a storage track in a classification yard, the combination of,

` (a) means responsive to the presence of said car on said storage track for registering continually a signal Whose value varies proportionately with the speed of said car as it moves along said storage track,

(b) means for detecting when said vehicle substantially reaches said coupling point, and

(c) means responsive to said detecting means and said registering means to provide an indication of the coupling speed of said car in accordance with the value of the signal registered by said registering means at the time when said detecting means detects that said vehicle is substantially at said coupling point.

12. The combination specified in claim 11 wherein said detecting means is a motion detector etfective'to detect when said car substantially reaches said coupling point in accordance with whether or not said car is moving` on said Alstorage track.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Ser. No. 320,937 (abandoned), Rabourdin (.P.C.), published May 25, 1943.

EUGENE G. BOTZ, Primary Examiner.

JAMES s. SHANK, Examiner. 

3. IN A CAR RETARDER CONTROL SYSTEM FOR A RAILWAY CLASSIFICATION YARD HAVING A CAR RETARDER FOR ADJUSTING THE SPEED AT WHICH THE CARS BEING CLASSIFIED COUPLE ON THEIR ASSIGNED STORAGE TRACKS, THE COMBINATION OF, (A) REGISTERING MEANS FOR REGISTERING THE SPEED OF A FIRST CAR ON ITS ASSIGNED STORAGE TRACK, (B) DETECTING MEANS FOR DETECTING WHEN SAID FIRST CAR REACHED ITS COUPLING POINT, AND (C) MEANS RESPONSIVE TO SAID REGISTERING MEANS AND SAID DETECTING MEANS FOR CONTROLLING SAID CAR RETARDER IN ACCORDANCE WITH THE SPEED OF SAID CAR AT SAID COUPLING POINT. 